1 Ganglia-groups of neuron cell bodies that lie peripheral to the central nervous system in vertebrates. 2  Bipolar neurons-cell body located near the middle of the axon; characteristic of retinal neurons. 3  Unipolar neurons-cell body lies off to one side of axon; characteristic of sensory neurons.
The principal host for diamonds are rocks formed in the earth's mantle that are known as eclogite and peridotite that are carried to the earth's surface in magmas known as kimberlit e and lamproite.
The Rock Cycle. A few gemstones form in the mantle, but all gems are mined in the crust. The crust is made up of three kinds of rock, known in geology as igneous, metamorphic and sedimentary rock. These technical terms refer to the way in which the rock is formed.